MICROBIAL DISEASES OF MAN AND ANIMALS. 



647 



The cholera organism gains entrance through the mouth. 



Having succeeded in passing the acid secretions of the stomach the 

 vibrios probably develop with great rapidity in the small intestine. 



The peculiar conditions favorable to the development of the organism 

 in the intestine are unknown. A previous gastro-intestinal disturbance 

 is probably necessary even though slight. 



The organisms have rarely been demonstrated in blood cultures. 

 The gall bladder gives the highest percentage of positive cultures. 



'ill? 



1 



a. 



b. 



c. 



FIG. 114. Microspira comma. Colonies on gelatin plates, a, 24 hours old; b, 

 30 hours old; c, 48 hours old. (After Fraenkel and Pfeiffer from Williams.} 



Highly lytic and agglutinating sera can be developed experimentally, 

 but little or no antitoxic power can be demonstrated. 



Protective inoculation has shown considerably more encouraging 

 results than serum therapy. 



The cholera vibrios are eliminated in the discharges. Water and 

 uncooked food becoming contaminated with cholera excreta are the 

 chief means by which the epidemic is spread, so that its epidemiology is 

 similar to that of typhoid fever. 



